Batch production of micron size particles from poly(ethylene glycol) using supercritical CO2 as a processing solvent

The major advantage of using supercritical carbon dioxide (CO2) as a solvent in polymer processing is an enhancement in the free volume of a polymer due to dissolved CO2, which causes a considerable reduction in the viscosity. This allows spraying the polymer melt at low temperatures to produce micron size particles. We have used supercritical CO2 as a solvent for the generation of particles from poly(ethylene glycol) (PEG) of different molecular weights. Since PEG is a hydrophilic compound, it is a most commonly used polymer for encapsulating a drug. PEG particles with different properties may allow keeping a good control over the release of the drug. It has been possible to produce particles with different size, size distribution, porosity and shape by varying various process parameters such as molecular weight, temperature, pressure and nozzle diameter. A flow and a solidification model have been applied in order to have a theoretical insight into the role of different parameters. (c) 2006 Elsevier Ltd. All rights reserved.